I guess I can refer to at least half a dozen voices McColl employed.

He always said local singers must reflect indigenous approaches, (he had a knack of rubbing people up the wrong way) but that he was a performer. Hence a Salford lad (with Scottish parents to be fair) could effect a Highlands accent, a Glaswegian one, pure Manchester or a flat accent free voice at will.

He also employed a foil to Seeger's voice when accompanying in choruses etc which was often different again.

I love listening to his voice as it employed feeling and empathy with the subject. It isn't a single voice though by any measurement.

My late friend Tom Brown had been living in North Nottinghamshire for many years and most of the time sounded so, but once on stage, he was pure Norfolk...... I tend to be more "Northern" when delivering a monologue in a folk club than when addressing students in the lecture theatre or at a conference. When I used to sing rock, I was rather transatlantic in my voice but far more South Yorkshire in a folk club etc.

Comparing voices is a bit like comparing fingerpicking to strum. Musical masturbation.